Photoluminescent sensors or probes are a widely employed method of measuring analyte concentration, typically oxygen, within an enclosed space such as a package or container. Briefly, analyte concentration within a package or container can be measured by placing an analyte sensitive photoluminescent probe within the package or container, allowing the probe to equilibrate within the package or container, exciting the probe with radiant energy, and measuring the extent to which radiant energy emitted by the excited probe is quenched by the presence of the target analyte. Such optical sensors are available from a number of suppliers, including Presens Precision Sensing, GmbH of Regensburg, Germany, Oxysense of Dallas, Tex., United States, and Luxcel Biosciences, Ltd of Cork, Ireland.
Analytical instruments used to read such photoluminescent probes are commonly programmed with a calibration mode that permits calibration of the instrument by having the instrument read probes that have been exposed to mediums having known concentrations of the target analyte (e.g., setting the instrument to calibration mode, reading a probe that has been placed within a container that is flushed with certified tank gas containing 0% analyte, and then reading a probe that has been placed within a container that is flushed with certified tank gas containing a known concentration(s) of analyte such as 100% analyte).
While effective for accurately calibrating optical sensors, this calibration method is time consuming and expensive.
Accordingly, a substantial need exists for a low cost system and method for accurately and reliably calibrating instruments used to read photoluminescent sensors or probes.